Production of prestressed reinforced concrete units



FEEETI QIG. R. s. v. BARBER 2,394,227

PRODUCTION OF PRESTRESSED REINFORCED CONCRETE UNITS Filed April 25, 1944 3 Sheets-Sheet 1 flFeb- 1946. R. s. v. BARBER 2,394,227

PRODUCTION OF PRESTRESSED REINFORCED CONCRETE UNITS Filed April 25, 1944 3 Sheets-Sheet 2 I IN ve NTOI? a COG/QM MQ M* Feb. 5, 1946. R. s. v. BARBER 2,394,227

PRODUCTION OF PRESTRESSED REINFORCED CONCRETE UNITS Filed April 25, 1944 3 Sheets-Sheet 3 l e NTO Rs. v. ISMW (,U MM+ Patented Feb. 5, 1946 UNITED STATES PATENT OFFICE PRODUCTION OF PRESTRESSED REIN- FORCED CONCRETE UNITS Ronald Samuel Vernon Barber, Malvern, England, assignor to Dowsett Engineering Construction Limited, Malvern, England, a British company Application April 25, 1944, Serial No. 532,623

In Great Britain June 30, 1943 8 Claims. (Cl. 25-154) This invention consists of improvements in the of the difliculties arise from the fact that conproduction of pre-stressed reinforced concrete crete, although it sets comparatively quickly,

sleepers, and in this specification the term takes a long time to harden.

"sleepers includes similar beams. According to this invention when the reinforc- Processes and apparatus have been proposed 'ing wires have been placed in position in the for the manufacture of articles of reinforced production lines and when a mould (with its concrete in which reinforcing wires or like memperforated or slotted end plates) is in position bers of high tensile steel are subjected (prior to in relation to the wires at one station in the pro and during the setting of the concrete) to very duction line, the mould is filled with concrete at high tension so that when the concrete has hardthe said station and is then slid along the producened and the externally-applied tension on the tion line (and along the wires) to the position reinforcing wires is discontinued, the wires applyin which the setting and hardening of the conhigh and permanent compression forces to the crete is to take place. It is a feature of this inconcrete. vention that while the mould is at the filling sta- In the application of that process to the mass l5 tion it is mounted on a vibratory ta e p production of sleepers a number of problems form so that the correct vibration can be imarise. One relates to the assembling and filling parted to the mould and to the concrete therein of the moulds and the dismantling of the moulds. during and immediately after the filling opera- Another relates to the method of giving correct tion. vibration to the concrete when introduced into an The nature of this invention and of s s y the mould. A third relates to the means of applyfeatures will be appreciated from the following ing and maintaining the high tensionv in the description of a specific example in which it will reinforcing wires and for positioning said Wires be assumed that all the production lines are on in relation to the moulds. A fourth relates to one level (say ground level or bench level), althe movement of the moulds in the production though the invention is applicable in cases where lines. the production lines are on more than one level Broadly speaking this invention consists of a ay in t O t manner of manufacturing pro-stressed reinforced There may be a number of production lines in concrete sleepers in which the individual sleeper parallel and each line may accommodate a large moulds arranged in long series can run on tracks number say from twenty to forty sleeper moulds or rollers 01 other guides in the production lines: in series. There is an assembly bay atone end the moulds may be provided with rollers or of the production line (the feed end). At each wheels; or each mould may be supported on a end of each production line is a standardor trolley having rollers or wheels; or the moulds pedestal and the reinforcing wires are stretched may be guided and partly or wholly supported between these standards by known means such by the reinforcing wires; or the track of the proas hydraulic tensioning devices. A mould is an duction lines may have rollers like those which open-ended trough and it can readily be placed support a moving billet on the floor of a steelin position around the reinforcing wires at the rolling mill. feed end and as above described the mould is The general system to which the present inven- 40 mounted'on a vibratorytable. The end plates tion relates is one in which each mould comprises of the mould are then placed in position and an open-ended body portion with movable end these may conveniently be constructed as deplates which are perforated or slotted to locate scribed in U ted Sta s p t pp n the reinforcing wires which are stretched between 527 ,798.

upright standards or pedestals and accommodate Assuming that the first mould of a series is in a considerable number of moulds in series in a position on the vibratory table at the concreteproduction line. filling station. the concrete is poured into the It would be a great convenience, in mass promould which receives the correct vibration. duction, if the filling of the moulds with concrete F When the filling and primary vibration of the could be carried out at one station, e. g. at one mould are completed the mould is slid right along end (the feed end) of the production lines. It the production line and along the wires which would also be a great convenience if the original can slide through the orifices or slots in the end vibration of each mould during the filling operaplates) until the filled mould reaches its setting tion could also be carried out at one station, e. g. position at the far end of the line. Then the next at the feed end of the production line, say on a mould is similarly treated and transported to its vibrating table. position in line and this process is continued till It-is an object of the present invention to prothat production line is filled up.

vide means for fulfilling these requirements and It will be understood that the moulds may re for overcoming the normal difficulties above receive a secondary vibration (say from their upper ferred to, and it will be understood that most edges) by the use of a portable vibrator, and this secondary vibration is preferably carried out when the moulds have reached their setting position The moulds may be dismantled at their setting positions; or when setting is complete in one production line, the moulds of that line may be moved along to a dismantling bay at the end of the line.

It will be understood that at a concrete filling station, if there are several parallel production lines, the concrete hopper or like concrete-delivery device may be moved laterally to fill the moulds for any of the production lines. In the same way the vibratory table (on which a mould is supported during filling) may be moved laterally to receive the moulds for any production line.

In the example above described the assembly bay and filling station were arranged at one end of the production lines. In an alternative arrangement embodying this invention, the assembly bay and filling station are at a mid position in the production lines and after the moulds are assembled, filled and vibrated at said mid position, they can be slid along the wires in either direction.

Reference has been made to the movement of the moulds on rollers or the like, but it is within the scope of this invention to support or guide the moulds on the stretched reinforcing wires and to slide the filled moulds along said stretched wires (especially for short distances).

According to a modification, when the first mould has been filled and vibrated it is moved on the production line only sufficiently to allow the next mould to be brought into position for filling and vibrating. The second mold is coupled to the first so that as the first mould is drawn along the production line it draws the second mould with it. Each succeeding mould is similarly coupled to the preceding mould the moulds coupled in series being pulled along the production line step by step until the whole series has been completed and conveyed to its setting position.

It is explained above that the filling station may be at one end of a production line or may be arranged in the middle of a production line and the present modification is applicable in either of these cases, the main point of the modi fication being that the moulds are coupled like the coaches of a train and that the pull is applied to the leading mould.

Preferably the moulds are arranged in pairs side by side so that'each of the operations of filling, vibrating, coupling and shifting is applied to the two members of each pair in succession According to a further modification of this invention, arrangements are made for dealing with the case in which a delay may occur in the normal operations of mass production. For example there may be a delay in thesupply of moulds to the production lines or there may be a temporary stoppage in the supply of concrete or in'the operation of the vibrating table. In the event of any delay, the mould or moulds which have been filled are pulled to setting position in the production line and any grout adhering to the reinforcing wires between the filling station and the setting position is cleaned off the wires. It is important to prevent any concrete grout from spilling on to operating parts and therefore at the appropriate points where spilling might occur provision is made to protect any operating parts, e. g. by the use of bailles, trays, troughs or the like.

It will be understood that in carrying this invention into eifect a filled mould has to be removed from the vibrating table and this removal may be facilitated by raising the filled mould from the vibrating table or by lowering the vibrating table to free the filled mould.

If it is-necessary to utilise a production line to its full capacity, the last mould of a series need not be moved from the filling station when the operations of filling and vibrating that mould are completed. It may rest in that position until setting and hardening are finished. At the completion of the hardening it will be understood that the series of moulds can again be pulled along the production line to a dismantling bay, this operation being conducted step by step.

In the accompanying drawings:

Figure l is a plan of part of the production lines showing devices for introducing the moulds and for filling, vibrating, and sliding the moulds to their setting positions and for removing the moulds;

Figure 2 is an elevation corresponding with Figure 1;

Figure 3 is a diagram in perspective showing an assembled mould in proper relationship to the reinforcing wires; and I Figure 4 is a diagram in perspective illustrating a cleaning box for cleaning the reinforcing wires.

Referring to Figures 1 and 2, an assembly platform I2'is adapted to receive a mould l3 and to be brought into contact with a vibratory platform l4 which imparts vibration to the mould l3; and concrete grout is supplied to the mould through a filling device l5. Each production line has a track l6 with a succession of rollers H arranged at spaced intervals transversely to the track. Each production line has a series of parallel reinforcing wires l8 stretched right along the production line and so arranged as to be accommodated within all the moulds in that line so that thereinforcing wires will be embedded in the concrete. In practice the reinforcing wires are placed in a state of very high tension, but the means for supporting the wires and for applying the high tension are not shown as they form no part of this invention.

Referring to Figures 1, 2 and 3, the particular feature of the present invention lies in the fact that each assembled mould I3 is filled at the assembly platform l2 and is then passed along the production line (and along the reinforcing wires) to its position in the production line to allow the concrete to set and harden. The particular arrangement shown by way of example in Figures 1 and 2 includes means for introducing the empty moulds and for removing the moulds after the concrete has set and hardened and after the reinforcing wires have been severed therefrom. The track for introducing the empty moulds is shown at H); a turn-table for turning the empty moulds parallel with the production line is indicated at 20 and an elevator for raising the moulds up to the level of the production line is shown at 2|.

Referring to Figure 3, it will be seen that the mould is a hollow trough 22 open at its ends and arranged to embrace the reinforcing wires l8. Each end of the mould is provided with slotted end plates 23 which form the subject of a separate patent application. The mould 22 is provided with bars or runners 24 which engage with the rollers l1 so that each mould is capable of running freely on the rollers I! along the track Referring again to Figures 1 and 2, it is an important feature of this invention that when an assembled mould has been filled with concrete the empty moulds for each production line are brought to that line over the track [9, that the moulds thus introduced (generally in pairs) are turned (on turn-table 20) parallel with the production line and are then raised to the level of the production line by the elevator 2 I, the rollers I! at that point being temporarily removed.

The moulds are pulled along the tracks IE on to the platform I! in turn where they are fitted with the end plates and thereby fully assembled. Concrete grout is filled into the assembled mould which is vibrated and after completion of the operations of filling and vibrating, the filled mould is pulled away from the platform 12 along the production line to its setting position. After the concrete in the moulds has set and hardened, the moulds may be moved along the production lines and at that stage the reinforcing wires themselves form the haulage means or couplings between moulds in series. Here again the winch 25 is utilized so that the moulds in turn may be pulled into position for the severing of the reinforcing wires and for the removal of the moulds from the production line.

In the arrangement illustrated, a power driven conveyor 26 is diagrammatically shown and in this case the finished moulds are brought on to a vertically movable platform 21 and lowered by the elevator 28 into a position where they can be transferred to the power driven conveyor 26. It will be understood that the finished moulds can be brought to the platform 21 from either end of the production line.

In the arrangement shown the concrete filling device 15, the vibratory platform I4 and the elevators 2| and 28 can all be individually moved laterally into register with any production line.

Referring to Figure 4, it will be appreciated that after a filled mould has been moved along the reinforcing wires, the surface of the wires may carry a thin film deposited fromv the concrete grout. In the case of any delay in the sequence of operations, it would be undesirable that such a film should set and harden on the wires and in order to deal with such a contingency, a cleaning box 29 having slotted end plates 30, '3! is arranged to slide along the wires I8 and contains a pulverulent attrition agent like sand 33. In the actual arrangement shown in Figure 4 the box has a transverse partition 32 so as to divide the box into two compartments, one 33 containing sand moistened with water and the other 34 containing steel wool.

I claim:

1. A method of manufacturing pre-stressed reinforced concrete sleepers in which parallel reinforcing wires are placed in position in production lines and are subjected to tension, each mould is placed in position in proper relation to said wires and is provided with end plates which close the ends of the moulds and locate the wires, the mould, is filled with concrete and is then slid along the production line (and along the wires) to the position in which the setting and hardening of the concrete is to take place.

2. A method of manufacturing pre-stressed reinforced concrete sleepers as claimed in claim 1 in which when a mould has been filled with concrete grout, it is moved on the production line only sufiiciently to allow the second mould to be brought into position for filling and the second mould is coupled to the first and each succeeding mould is similarly coupled to the preceding mould so that a plurality of filled moulds coupled in series may be pulled along the production line (and along the wires) step by step until the whole series has been completed and conveyed to its setting position.

3. The method of manufacturing reinforced concrete blocks such as sleepers comprising, disposing a plurality of reinforcing wires in substantial parallelism and placing them under tension, forming a concrete block about said wires at a moulding station, sliding the freshly moulded block along the wires to a hardening station before it has appreciably hardened, allowing the concrete block to harden at the hardening station and to thus grip the tensioned wires, and thereafter severing the wires to free the hardened block.

4. The method of manufacturing reinforced concrete blocks such as sleepers comprising, disposing a plurality of reinforcing wires in substantial parallelism and placing them under tension, forming a concrete block about said wires at a moulding station, sliding the freshly moulded block along the wires to a hardening station before it has appreciably hardened, successively forming additional blocks of concrete about said wires at said moulding station and sliding each freshly moulded block along the wires to a hardening station before it has appreciably hardened,

allowing all of said concrete blocks to simultaneously harden, and thereafter severing the wires to free the hardened blocks.

5. The method set forth in claim 3 and in addition the freshly moulded block being subjected to vibration at the moulding station, immediately after moulding and prior to being advanced to the hardening station.

6. The method set forth in claim 4 and in addition each successively formed block being vibrated at the moulding station immediately after moulding and prior to being advanced to the hardening station.

'7. The method set forth in claim 4 and in addition a body of cleaning material being disposed about the reinforcing wires after each freshly moulded block has been moved to its hardening station, and moved along the wires to clean them.

8. The method set forth in claim 4 and in addition the successive blocks are formed by depositing concrete in moulds successively brought to the moulding station and each mould as filled is connected in series with previously filled moulds, all filled and connected moulds being simultaneously advanced after each filling operation.

RONALD SAMUEL VERNON BARBER. 

